为考察纳豆菌糖肽（BNGP）对正常状态及脂多糖（LPS）激活状态巨噬细胞的免疫调节作用，本文用不同浓度的BNGP单独处理或LPS和不同浓度的BNGP共同处理RAW264.7巨噬细胞，采用噻唑蓝（MTT）比色法检测细胞增殖作用，中性红吞噬试验检测吞噬能力，Griess试剂检测细胞培养上清液中NO含量，酶联免疫分析法（ELISA）检测细胞培养上清液中细胞因子（IL-1β、TNF-α）、促炎介质（PGE2）含量，Western Blot检测COX-2和iNOS蛋白表达水平。试验结果表明：BNGP在62.5~500 μg/mL浓度范围内能提高正常状态的RAW264.7巨噬细胞的代谢活力，增加NO、IL-1β、TNF-α、PGE2的分泌量，提高COX-2和iNOS的表达量，高浓度（>125 μg/mL）能增强巨噬细胞的吞噬能力；当细胞处于LPS激活状态时，BNGP在62.5~500 μg/mL浓度范围内能抑制IL-1β、TNF-α、PGE2的分泌，浓度为500μg/mL时可抑制NO的产生及iNOS的表达，高浓度（>125 μg/mL）则能下调COX-2的表达。

The immunomodulatory effects of Bacillus natto glycopeptides (BNGP) on normal and lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were investigated in the present study. After treatment with different concentrations of BNGP or combinations of LPS and BNGP in different concentrations, the proliferation of macrophages was detected by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, the phagocytic activity was detected by neutral red phagocytosis experiments, and the content of nitric oxide (NO) in the cell culture supernatants was detected by the Griess reaction. The production of cytokines (IL-1β, TNF-α) and pro-inflammatory mediator (PGE2) in culture supernatants were measured using an enzyme-linked immunosorbent assay (ELISA), and the expression levels of iNOS and COX-2 were detected using western blotting. The results showed that at concentrations of 62.5–500 μg/mL, BNGP enhanced the metabolic activity of macrophage RAW264.7 in the normal steady state, increased the secretions of NO, IL-1β, TNF-α, and PGE2, and improved the expression levels of iNOS and COX-2; at high concentrations (>125 μg/mL), it enhanced the phagocytic capacity of macrophages. For the LPS-stimulated macrophages, BNGP inhibited the secretions of IL-1β, TNF-α, and PGE2 at concentrations of 62.5–500 μg/mL, inhibited the production of NO and the expression of iNOS at concentrations of 500 μg/mL, and downregulated the expression of COX-2 at high concentrations (>125 μg/mL).

国家自然科学基金(31160337)